Unit 3: The Mole Concept, Chemical Formula and Equation

Which chemical equations is balanced?

Persamaan kimia manakah yang seimbang?

• NaOH _(aq) + H₂SO_{4 (aq)} → Na₂SO_{4 (aq)} +H₂O _(l)

• Zn(NO₃)_{2 (s)} → ZnO _(s) + 2NO_{2 (g)} + O_2(g)

• Mg _(s) + 2HCl _(aq) → MgCl_{2 (aq)} + H_{2 (g)}

• CaCO_{3 (s)} → CaO _(s) + 2CO_{2 (g)}

Equation above show the process of decomposition of hydrogen peroxide. Which of the following statement is correct?

Persamaan di atas mewakili proses penguraian hidrogen peroksida. Pernyataan yang manakah benar?

• The product of the reaction is oxygen

  Hasil tindak balas adalah oksigen

• The reactant are water and oxygen

  Bahan tindak balas adalah air dan oksigen

• Three moles of hydrogen peroxide is decomposed into two moles of water and one mole of oxygen

  Tiga mol hidrogen peroksida terurai kepada dua mol air dan satu mol oksigen

• Hydrogen peroxide burn and produce water and oxygen

  Hidrogen peroksida terbakar dan menghasilkan air dan oksigen

Boric acid is used to produce fibre glass textile. What is the chemical formula of boric acid?

Asid borik digunakan dalam penghasilan tekstil kaca gentian. Apakah formula kimia bagi asid borik?

• H₃B

• H₂SO₄

• H₃B₂

• H₃BO₃

Which of the following is M?

Antara berikut, yang manakah M?

• Copper(II) carbonate

  Kuprum(II) karbonat

• Copper

  Kuprum

• Copper(II) hydroxide

  Kuprum(II) hidroksida

• Copper(II) oxide

  Kuprum(II) oksida

Insect repellent has the formula of CH₃(CH₂)₅CHCHCHO. Determine the relative molecular mass of this substance.

[Relative atomic mass: H = 1; C = 12; O = 16]

Penyembur serangga mempunyai formula CH₃(CH₂)₅CHCHCHO. Tentukan jisim molekul relatif bagi bahan ini.

[Jisim atom relatif: H = 1; C = 12; O = 16]

• 110

• 120

• 130

• 140

What is the molecular formula of compound with empirical formula C₂H₄O?

Apakah formula molekul sebatian dengan formula empirik C₂H₄O?

• C₃H₇COOCH₃

• C₃H₇COOH

• C₄H₉COOH

• C₂H₅OH

Element X and element Y have proton number of 19 and 8 respectively. What is the relative molecular mass of a compound formed between X and Y?

[Relative atomic mass : X = 39 ; Y = 16]

Unsur X dan unsur Y masing-masing mempunyai nombor proton 19 dan 8. Berapakah jisim molekul relatif bagi sebatian yang terbentuk antara X dan Y?

[Jisim atom Relatif : X = 39 ; Y = 16]

• 94

• 35

• 46

• 71

When zinc carbonate powder is heated strongly, it produces colourless gas M. What is gas M?

Apabila serbuk zink karbonat dipanaskan dengan

kuat, gas tanpa warna M dihasilkan. Apakah gas M?

• Hydrogen gas / Gas hidrogen

• Carbon dioxide / Karbon dioksida

• Inert gas / Gas adi

• Oxygen gas / Gas oksigen

State the observation when gas M passed through the lime water.

Nyatakan pemerhatian apabila gas M dilalukan ke atas air kapur.

• Lime water turn blue / Air kapur berubah warna ke biru

• Lime water turns cloudy / Air kapur menjadi keruh

• Nothing change / Tiada perubahan

• Black precipitate form / Mendakan hitam terbentuk

Write the chemical equation for the reaction in the experiment above.

Tuliskan persamaan kimia bagi tindak balas yang berlaku dalam eksperimen di atas.

• ZnO₃ → ZnO + CO₂

• ZnCO₂ → ZnO + CO₂

• ZnCO₃ → ZnO + CO₂

• Zn → ZnO + CO₂